Description:
The dematiaceous molds appear dark because of their ability to produce melanin. They are found everywhere in nature, and live as saprophytes or as plant pathogens. However, humans can accidentally acquire skin and subcutaneous infections from them; on occasion, they can become invasive. A convenient way to classify them is by the type of infection (the description of each will be presented in more detail on the next page):
- Superficial infections
- Mycetoma
- Chromomycosis (also known as chromoblastomycosis)
- Phaeohyphomycosis
In the laboratory, dematiaceous molds are often grouped by slow growing species and rapid growing species.
Common Species:
Species include:
- Hortaea werneckii causing tinea nigra
- Piedraia hortae and Heocytalidium dimidiatum causing black piedra
- Neoscytalidium dimidiatum casing hyperkeratosis (typically tropical, not covered any further here)
Species causing mycetomas include: - Curvularia spp
- Madurella spp
Some hyaline molds can also cause mycetomas: - Pseudallescheria boydii
- Acremonium spp.
Agents of chromomycosis (chromoblasomycosis): - Cladophialophora carrionii
- Fonsecaea pedrosoi
- Phialophora verrucosa
Phaeohyphomycosis can be caused by:- Cladophialophora bantiana
- Rinocladiella mackenziei
- Verruconis gallopava, and Exophilia, Alternaria, Exserohilum, Bipolaris, Exophiala, Exserohilum, Bipolaris, and Curvularia spp.
More information follows on several of these species.
Epidemiology and Disease:
These saprophytes and plant pathogens are ubiquitous in the environment although certain ones are more likely to occur in tropical vs. temperate areas.
Most of the superficial infections mentioned above are caused by organisms more likely to be found in tropical areas, and thus will not be covered in any further detail in this course.
